Count 1 in Binary

Count how many 1 in binary representation of a 32-bit integer.

Example

Given 32, return 1

Given 5, return 2

Given 1023, return 9

public class Solution {
    /**
     * @param num: an integer
     * @return: an integer, the number of ones in num
     */
    public int countOnes(int num) {
        int count = 0;
        for (int i = 1; i <= 32; i++) {
            if ((num & 1) == 1) {
                count++;
            }
            num = (num >> 1);
        }
        return count;
    }
};